The levels of lymphocytes, blood lymphocytes subsets (CD3+, CD4+, CD8+, DR+, CD25+, CD4+, CD45RA+, CD4+, CD29+ cells) and sIL-2r of 10 patients affected by relapsing-remitting multiple sclerosis were serially studied. The identification of the activity of the disease was made by gadolinium-DTPA (Gd-DTPA) MRI. The immunological determinations and the MRI of the brain and spinal cord were performed every 14th day for a period of three months. No significant difference of the immunological values were found between the presence and the absence of Gd-DTPA enhancing areas, except lymphocytes (p < 0.05). These immunological parameters, evaluated in the peripheral blood, are not a marker of disease activity in relapsing-remitting MS patients.